Thursday 30 July 2020

Erratic Wind Power: the Great Grid Balancing Act

Some years ago on another blog I wrote several posts noting how problematic was the rise in erratic forms of electricity generation (especially wind power) which presents the operators of grid systems with challenges that sometimes call upon extreme (and inefficient) (and costly) solutions.  Germany is the worst. 

The underlying physical facts have not much changed; and the amout of wind power has increased considerably.  But the operators are good engineers - and regulators let them spend whatever they need to (and send us all the bill) - just keep the bloody lights on! So, by and large, the lights have been kept on, albeit at the cost of ever more of those extreme, inefficient and expensive solutions.

However, new solutions are hoving ever closer into view as practical propositions.  Most of what I summarise below is not red-hot news in the industry; but a lot of MSM types are suddenly catching up with it.
  1. Storage:  it has long been the quip in physics labs around the world that "if you can invent a truly economic means of storing electricity, you can name your university after yourself".   I'm hoping it's obvious how cheap storage would contribute to the erratic windpower problem.  Well, a bit like The Cure For Cancer (see BTL comments here), there hasn't been a single mighty breakthrough; rather, a lot of impressive incremental improvements, not least in batteries - and we're getting there.  So, there are people building solar + battery combos, and massive grid-scale batteries at cunning points on the system, without subsidies: always the acid test.  It's early days: but we're getting there.  (It's not just batteries, either.)
  2. HydrogenI've written about this quite recently (and subsequently so, inter alia, has the DTel).  I know there are loads of sceptical views out there: but believe me, the amount of private money and effort going into this is truly immense.  How does it contribute to the erratic windpower problem?  Easy: storing hydrogen is much easier than storing electricity, and negative-price electricity (offpeak windpower at times of big surplus: solar power in many, errr, sunny parts of the world) can generate quite cheap hydrogen, via electrolysis.  And hydrogen can be used for lots of applications - including generating electricity again!   (I'm summarising heavily because it's a very big picture that's rapidly developing.)
  3. Demand-side response & aggregator systems: when the price of electricity goes negative, you can pay people to take it off your hands.  Likewise, when it goes through the roof at times of peak usage, you can pay people to stop using it.  Who are "people"?  Well, just about anyone and any firm or organisation that can, with a bit of thought (and maybe a bit of investment), vary their demand in response to sufficiently juicy price incentives.  To make this work on a big scale requires a lot of software sitting in some aggregator's systems, crunching the most epic quantities of data real-time and transacting millions of times in small quantities.  There are more people with this vision than are making much money out of it - yet.   
On this last category of tool: the sole reason those recent, and thus far quite successful electricity-market insurgents Ovo and Octopus are in the market as suppliers (an otherwise rather unrewarding business) is to play this game using the ever-expanding fleet of electric vehicle batteries, as soon as this can become a reality. They expect to clean up. As noted in the linked article, "It requires dedicated two-way charging equipment that can also communicate with the vehicles, as well high-level aggregator control systems. However all of this technology exists". Yes - and right now Elon Musk (Tesla) refuses to make batteries that will do 2-way charging! To be fair, it can shorten battery life significantly, and will require all sorts of potential hazards (and consequent insurance issues) to be resolved. Also warranty issues: if (e.g.) Ovo is offering a stonking real-time pricing deal that incentivises car owners to cane their batteries for £££, they will destroy them quite quickly.

It's all part of the vast, mostly-untapped world of demand-side response potential.  We are going to need it all, eventually: and storage, and hydrogen.  The good news is, this (like hydrogen replacing natural gas) is the kind of phenomenon that can grow slowly (at first), in small but steady degrees.  Contrast with the unicorn of carbon-capture-and-storage - everyone can describe it, some people believe in it, but it doesn't exist - which can only be done by hitting critical mass immediately.  That's hard.  That takes public money.

The other beauty of DSR is, early adopters will love it (£££ + prestige) and then, at both the individual and the corporate level, it will become fashionable - always the best form of promo.

So:  balancing a grid which supports a large amount of windpower and solar will never be cost-free - there has to be some flipside to sources of energy with almost zero direct variable cost (i.e. no fuel) - but it is going to get ever more efficient.



DJK said...

Energy storage is interesting. And it obviously complements the intermittent nature of renewables (wind and solar).

The demand side fluctuates as wll as the supply side. In part this is predictable (diurnal and weekly cycles) and in part random. So even back in the 50s, grid scale storage was felt to be needed to balance the nuclear base load against fluctuating demand. The solution then was pumped storage. And those pumped storage plants are still avaiable today.

The difference now is that not only is the demand fluctuating, but the supply is too. Again, it's partly predictable (solar at night) and partly random.

Grid scale chemical batteries are one solution. And there are others such as electrolysis of water, or raising heaving weights up mineshafts, compressing air, etc.

Then there are the 'natural' energy sinks. Millions of cars plugged in to charge are one. I read about an industrial cold storage that was used as a battery. Charge it by using surplus electricity to reduce the temperature below normal, get that electricity back (net) by switching the plant off and letting the temperature rise. Somewhat similar, is hydro, particulary in Norway. When the wind blows in Scotland, export electricity to Norway to power their consumers, allowing the Norwegians to conserve their hyrdo power; when the Scottish wind fails, let the Norwegians run their hydro power at full tilt and import their surplus.

So yes, a bit like the incremental improvements in cancer (and Covid-19) care. No need for a big bang improvement, just batallions of little solutions.

The really tricky one for the UK is those long (~week) periods in January/February when you can get freezing weather and no wind. Batteries and so on are good for smoothing out day to day fluctuation, but those windless cold spells are when you really need to fire up the mothballed fossil fuel plant.

Elby the Beserk said...

"Demand-side response & aggregator systems: when the price of electricity goes negative, you can pay people to take it
off your hands."

Who exactly do you mean by "you", Nick? Me by any chance?

Lord T said...

A complex business but why would you pay someone to take it off your hands? Wouldn't you just let them have it free or waste it instead?

Anonymous said...

Slightly off topic but if Scotland becomes independent there is no way that the English consumer will agree to carry on paying the current hidden subsidies given to remote Scottish windfarms.

dearieme said...

Beware of bad analogies. About Covid ND wrote: "rather like cancer...". But it isn't - cancer is a thousand diseases with similar symptoms. Covid-19 is one disease.

As for hydrogen: fingers crossed. But it would be wonderful if someone could develop a fuel cell that ran on methanol - then methane reserves would become valuable as a source of transport fuel that could be used with a high thermodynamic efficiency.

Anonymous said...

"Current DMFCs are limited in the power they can produce, but can still store a high energy content in a small space. This means they can produce a small amount of power over a long period of time. This makes them ill-suited for powering large vehicles (at least directly), but ideal for smaller vehicles such as forklifts and tuggers"

Tuggers? Something like this?

Thud said...

This is all way beyond my pay grade but I was quite happy with a world running on gas and oil, silly me.

Nick Drew said...

Lord T - why would you pay someone to take it off your hands? Wouldn't you just let them have it free or waste it instead?

Easy. Market price is -10. You, a windfarm, have a surplus. So "someone" can buy it at -10, i.e. the market will "cost" him -10 (= pay him10); and you will be left paying the market 10 to shift your surplus. But maybe "someone" doesn't really want the hassle of dealing direct in the market, or can't actually access the wholesale market (which is the case for most people). So you split the difference and pay him 5 (instead of paying the market 10); and he gets 5 (instead of 10 + hassle)

(If he's dumb enough to settle for "free", well, so be it, clever you! But he can do better than that.)

Elby Who exactly do you mean by "you", Nick? Me by any chance?

Yep! This is NOT a recommendation, but check out the Octopus "Agile Tari

david morris said...

Comment ?

Don Cox said...

" Batteries and so on are good for smoothing out day to day fluctuation,"

So far, they seem to be good only for smoothing out minute-to-minute fluctuations, in order to keep the A/C frequency steady.

The quantity of batteries tat would be needed to power London for several days is staggering, and I think recycling the units at the end of their short lives is an insoluble problem.

Don Cox

Nick Drew said...

David, Don -

Overall, I have some regard for the competence of National Grid, so I'd give 'em the benefit of the doubt and assume their new set of scenarios is a worthwhile exercise (tho I haven't analysed them in detail yet)

[BUT - always remember they have an agenda, namely: please Mr Regulator, make us spend ever more money on capital projects that you allow us a guaranteed rate of return on]

"Electrolysis is regarded as no more than a niche operation, mopping up surplus wind power for use in aviation and shipping, partly because of its greater purity. This rather puts the kybosh on some of the exaggerated claims made about electrolysis recently" - i.e. most H is produced from methane in this scenario

This, to me, is part and parcel of what I wrote earlier, namely that H is a technology that can start small and simple (using methane initially) but grow, in a nice smooth manner, to big & more sophisticated (electrolysis) in due course.

For example, you can have up to 10% H in the EXISTING gas grid (and reduce the amount of nat gas to 90%, in a simple blend) without any modifications whatsoever. One of the UK distribution companies is going to run a 10+90 test unilaterally, and see if anybody notices! (There are a couple of physico-chemical differences but here isn't the place to go through them)

A lot of commentators underestimate the amount of negative-price electricity there is going to be in future, without storage and/or hydrogen production to soak it all up. There are places in the world where solar PV, even without a subsidy, is an absolute no-brainer, PROVIDED you have a way of making good use of what would otherwise be negative-value output. And H will give batteries a serious run for their money - in fact, will almost certainly be cheaper.

E-K said...

Does all this presume that our heavy manufacturing continues abroad abroad using coal powered stations ?

(Is the Christmas toy barge still coming up from China this year ?)

patently said...

"Germany is the worst".

Surely Germany is the wurst?

Sorry... I'll get my coat.

anon said...

no no, please stick around! we just love stuff like that

(though I shall forbear from calling you a brat ...)

Lord T said...

Nick, I understand the mechanics of it but still struggle with the concept of paying someone to take it away. I have had a house tidy and am disposing of clothes etc. that are perfectly good. I have extra goods I don't need. I don't pay people to take them away, although I could, I give them to a charity shop or bin them.

Maybe this is why my skills are not in demand in the economics area.

Nick Drew said...

this is why indeed ..!

but look, there's no charity in this**

maybe (some) individuals won't rush for this - loads of people don't behave in the way economists consider to be rational - but think of a bus company with a large fleet of electric buses; massive battery capacity, massive recharging needs: but still not really a candidate for playing the wholesale electricity markets themselves (the most risky markets on earth)

then along comes Mr Octopus and offers to split the difference with them on negative power prices if they'll charge their batteries when he tells them to: and an even better deal if they'll turn their entire charging / discharging schedule over to him for optimising, PROVIDED all the buses are fully charged by (say) 06:00 each morning, or whatever is BusCo's irreduceable bottom line requirement

incidentally there are people signing contracts to do this (in a proto-way) right now

and why wouldn't they? so long as all those insurance / warranty etc issues are properly taken care of

**well, I suppose there could be charity - a neat PR gimmick for an energy firm!

estwdjhn said...

But why pay anyone anything, when you can just disconnect your solar panels from the grid instead of pushing power there. Even wind turbines can be shut down on a windy day - about the only people who really need to carry on stuffing power in the grid are regardless of demand are the nuclear boys.

The only reason for the absurd significant negative pricing we get at the moment is the subsidy and pecking order regimes we have now incentivise the operation of the wrong sort of generation. When there is surplus, we should be running the nuclear (and in the context of short term spikes and drops fossil) baseload (without paying them, they need to keep generating), and then use the wind and solar as load following.
If it wasn't for a subsidy regime which makes it viable to keep sticking wind output into the grid when the price is negative (instead of hitting the disconnect button the moment the spot price turns negative), we'd never see significant negative spot prices, as production would trim back naturally to match demand as soon as prices go to -1p/unit.

Matt said...

@ estwdjhn

If you can forecast when wind/solar will drop off (to below economic value) and then pick up again (to above economic value) then there are better ways to make money than electricity generation.

Predicting the EuroMillions, Grand National, Super Bowl etc would all be nice earners.

Nick Drew said...

Matt - in fact, short-term wind forecasts are starting to get much more accurate: strikingly so

everything improves when there's a big enough incentive

Lord T said...


Thank you for that simplification. That I do understand. I wouldn't have described it as paying people to take it away though which is where I had the issue.

david morris said...

This from Timmy, ND